Log system for ships



Oct. 11, 1938. A. P DAvls LOG SYSTEM FOR SHIPS Filed Jan. 6, 1934 3 Sheets-Sheet 1 @mix ' ORl gil SOO@ .62M

Oct. 11, 1938. A. P DAVIS r bos SYSTEM. Foa SHIPS Filed Jan. 6, 1934 3 Sheets-Sheet 2 www R .w N um mm A .l N f Il @l o m s QN :v m wm. awww Nw w wm f l .Si E hv( ww bw :Q mm mN Sv @u N QN wm Nw ww um "e Q ,nl ww s s NNN EN wN Rw a. NN*

ATTORNEY5 Oct.` 11, 1938. A, P DAVIS LOG SYSTEM FOR SHIPS Filed Jan. 6, 1954 3 Sheets-Sheet 3 NWN V LL C ggg Patented Oct. `11, 1938 UNITED STATES PATENT OFFICE LOG SYSTEM FOR SHIPS Application January 6, 1934, Serial No. 705,635

3 Claims.

This invention relates to the navigation of propeller driven vessels, and particularly to the determination and transmission of data as to the speed of the ship and the distance tr-aveled.

The main object of the invention is to provide a system which will count and integrate the revolutions of the ships propellers and derive therefrom the individual and average propeller shaft revolutions per minute, differentiate revolutions, and compute the total miles traveled by the ship.

Another object of the invention is to provide a system which will transmit the resultant readings to various parts of the ship.

Further objects of the invention, particularly1 in the details of the apparatus and electrical circuits involved, will appear from the following specification taken in connection with the accompanying drawings, in which Fig. 1 is a diagram illustrating the general aspects of the system by typical elements and connections for one specific embodiment,

Fig. 2 is a diagrammatic view illustrating the comparing and computing parts and showing their interrelation,

Fig. 3 is a sectional view showing the electrical apparatus applied to the propeller shaft and adapted to transmit the revolution thereof as alternating current of corresponding frequency, and

Fig. 4 isla side view with parts in section of the apparatus shown in Fig. 3.

In the system outlined in Fig. 1, alternating currents' of frequencies corresponding to the o revolutions of each propeller shaft 6 and 1 are transmitted by conductors IIIIl, IIII to the twoshaft indicator A, containing comparing and computing mechanism to derive the readings as shown. At a, ak indicators 'show the total revolutions of the port and starboard propeller shafts and at b, b indicators show the revolutions per minute of each shaft. At a" the average total revolutions of both shafts appear on an indicator, and at b" the indicator shows average R. P. M. of the two shafts. The directions of rotations, forward or reverse-are given at c, c and at the bottom of the board 'at d an integrating indicator gives the reading of the total mileage. The percent correction of the mileage to compensate for accumulated matter on the bottom and propeller slippage appears at e, and isset by handle 8 and from time to time as the obstructive deposits increase and as propeller slippage varies with the R. P..M.

The indicator is located in the engine room and contains most of the calculating and transmitting mechanism.

In addition to the indicators located in the engine room and contained in the two-shaft indicator bo-ard A yother indicators are placed in desired positions around the vessel to reproduce the readings of the various indicators. Thus conductors ID3, |04 and |85 repeat the indications of b, b and b" on the indicator board B located in the pilot house, conductors |06 and |01 repeat indications of a" and b on the board D in the chart house and conductors |08, IIIS and I I0 repeat the reading of d on the boards in the pilot house and chart house.

Referring to Fig. 2 showing the mechanism l within the two-'shaft indicator A the alternating current connection |00 from the port shaft revolution transmitter P drives the port propeller revolution motor I0 and similarly the current carried by conductor IOI from the starboard shaft revolution transmitter drives the starboard propeller revolution motor I8' at the respective speeds of said shafts 6, 1. 'I'he port and starboard revolution readings a, a are provided by counters 35, 35' having their gears r 36, 36 driven from the gears II, II of motors l I0, I8 respectively. And the average .revolution reading is given by the counter 4I having its gear 48 driven from the gear 39 of the differential 29, the one side of which is driven through gears II, 31 from the motor I8, while the other side is driven through gears II', 31 and 31" and 38 from the motor Ill. The gearing of the differential 29 is such that the output gear 39 averages the revolutions of the input gears 31, 38.

In order to derive the R. P. M. readings indicated at b, b', the gears II, II of motors I0, I0 each drive one side of diiferenials I3, I3' through gears I2, I2', the other input sides of Said differentials I3, I3 being driven from the constant speed motor 28. The rotor of the constant speed motor 28 drives its gears 21, 21' at a predetermined constant rate, these gears being engaged with slide gears 23, 23 carried by the friction rollers 22, 22', which rollers run on the friction discs 24, 24 which through shafts 25, 25 and gears 26, 26' and I4, I4 drive the upper sides of the differentials I3, I3'. The output gears I5, I5' of differentials I3, I3 are driven at a rate which is the difference between the rates of rotation of the gears 26 and II for differential I3 and 26 and II' for differential I3. The output gear I5, I5' of differential I3, I3 drives the worm i8, I8' through gear I6, I6 and shaft il, il', and so drives the worm wheeli, i9' which meshes with the worm i8, I8'. This worm wheel i9, I9' is threaded on a nonrotatable'shaft 20, 20 rotatably carrying the slide gear 23, 23 and friction roller 22, 22', and the rotation of gear i9, i9' moves the shaft 20, 29 lengthwise to vary the position of the friction roller 22, 22' on the friction disc 2li, 2li and so vary the speed of the gear 2S, 26 with relation to the speed of the time motor gear 2l, 2l', the relations being such as to always bring the speed of the gear 26, 26 to be the same as that of the gear il, and so to slow down and finally stop the rotation of the differential output gear l5, l5.

For every change in speed of the motor i9,

| there is, therefore, a corresponding change in the speed of the gear I5, l followed immediately by a shift of the friction roller 22, 22 to again bring the gear l5, l5 to rest. At each instant the position of the friction roller 22, 22 relative to the center of the friction disc 29, 2li' measures the difference in speed between the motor lll, lll and the time motor 28. The shaft 2|), 29 is keyed to slide in the support 2|, 2| and the gear 30, 3U' is connected to rotate with the Worm wheel I9, i9 so that the rotation of the transmitter gear 3|, 3| meshing with gear 30, 30 is proportional to the difference in speed between the motor lil, lil' and the motor 2% is a self-synchronous motor driven at constant speed. Consequently the pointer 33, 33 of shaft 32, 32 rotating with gear 3|, 3| is moved over a properly calibrated scale to give the indications of the port and starboard propeller R. P. M. on the transmitter dials b, b of the two-shaft indicator A in the engine room.

To obtain indications of the average R. P. M. the output of the port differential i3 is connected to one side of the differential Sli, to the other side of which is connected the output of the starboard differential i3'. The port connections comprise the gear i6, shaft il, bevel gears 63, shaft ll and bevel gears 35, While the starboard connections comprise spur gear I6 and 16. The output gear il of the differential 69 rotates at the average speed of the input from port and starboard and is meshedto the gear i8 which through worm 50 and Worm Wheel 5| drives the shaft 52 connected to indicate the average R. P. M. at b of the two-shaft indicator A.

The total mileage is derived from the average revolutions as developed by the output gear `139 of the differential 29. This gear 39 drives the shaft 56 carrying the friction-disc 57, which is, therefore, rotated at the speed proportionate to the average speed of the two propellers. The mileage, however, is not directly proportional to this average speed but varies with the foulingof the ships bottom and the relative propeller slip at the different speeds. Characteristics for these two variables `are accumulated in the correction cam Wheel 65 and its mounting so as to vary the position of the friction roller 5l on the disc 5l and so vary the speed of the slide gear 59 and its meshing gear 60 driving the gear 62 of the mileage counter 63. The correction cam wheel 65 rotating on and about the center 6B has a cam groove 1| inwhich runs the cam roller 'i2 of the rod 13 rotatably carrying the friction roller 58. 'I'his cam Wheel 65 is carried by an adjustable bracket 61 in which is Yrotatably mounted the shaft 69 of the worm l0. At its other end the shaft 69 is driven by the bevel slide gear 68 meshing with the` bevel gear 68 on shaft |59. As the speed of the propeller shafts increases the relative slip will also increase and the gears 68, B8', shaft 69 .and worm lwill turn the worm wheel 65 to move the friction roller 58 inward toward the center of the friction disc 5l. In this Way a larger number of average revolutions will be required to indicate the same mileage, and this correction is automatically taken care 0f as the propeller speed changes.

There is also a further increasein slippage when the resistance of the hull is raised by the accumulation of barnacles and other fouling. To provide correction for this accumulated obstruction the frame or bracket 5l carrying with it the cam wheel 65 is threaded to theshaft l carrying the hand crank l5. As this crank is turned', clockwise, for instance, the frame or bracket 6l is drawn to the right to move the friction roller 59 toward the center'of the disc 5l to increase the slip and maintain the mileage more accurately corresponding to the actual mileage of the ship. This turning of the crank l5 is progressively made upon repeated estimations ofthe accumulation of the barnacles or other deposit, and when the ship is finally drydocked and cleaned the handle 'i5 is, of course, turned back to starting position. A gear i8 on the shaft lll turns a gearl9 carrying the pointer 9@ and-indicating at e the percent correction being applied for the accumulated deposits on the bottom of the ship.

In order to provide for the transmission of the developed indication of the two-shaft indicator A, the mileage transmitter 6| is provided for the mileage count, the port and starboard R. P. M. transmitters 3&5, 315 and the average R. l?.l M. transmitter 5d are provided for the speeds. The R. P. M. transmitters Ell, 34 and'll are of the self synchronous type connected by Wires |03, 09 and |95 to the driving means for the indicators of the two-shaft repeater B located in the pilot house. Similarly the mileage transmitter 6| of the self synchronous type (Davis Patent No. 1,977,624) is connected by wire |69 and |99 to the mileage indicator 80 also located in the pilot house (Fig. 1). a branch H0 of wire |08 also transmits the mileage reading to the mileage repeater D of the chart house, and wires it, lill carry respectively the average R. P. M'. and the average revolutions to the indicator C located in the chart house.

In the two-shaft indicator/A the direction signais c, c' are provided by dials 8|, 8|' and pointers 82, 92', the pointers being loosely connected to shafts 83, B3 and restricted to a limited arcuate movement by stops 3d, 8&3. On each change of direction the pointers 92, 82' will be moved from one side to the other against the corresponding stop, after which the drive shafts 83, 83' will slip with relation to the pointers. The dials 8|, 8|' bear legends Ahead and Astern against which the pointers 82, 82 are read indieating Whether the corresponding propeller shafts are turning in such a direction as to drive the ship ahead or astern.

In Figs. 3 and 4 the propeller shaft revolution transmitter is shown in place on the propeller shaft 6. This transmitter induces and controls the output voltages electromagnetically and comprises two semi-circularshells |20, i 2| carrying bosses |23 for bolt fastenings |24 tightened to .clamp the shells |20, |2i on the shaft as shown. Surrounding these shells at one side are the semi-circular, laminated iron sections |25,

. |26 clamped around the shaft by the fastening two-laminated iron pole pieces |28, |29 clamped,

to the shaft 180 from each other and magnetically connected to the rings |25, |26 by laminated iron sections |30, |3|. The cylindrical periphery of the shaft structure not occupied by the surface areas of the rings |25, |26 and pole pieces |28, |29 is covered by the sections |32, |33 of a copper shield clamped in place on the shaft and maintained in spaced concentric position by the bushing supports |34, |35, |30, |37, |38 and |39. These parts on the shells |20, |2| comprise the rotary part of the transmitter.

Around this is the stator or armature in generally semi-circular form comprising the slotted armature core |40 supported concentric with the propeller shaft by the housing |4| of cast metal. Three laminated iron field cores |42, |43, |44 are carried by the other side of the housing |4| and are magnetically connected to the armature core |40 by extensions |45 on each field core. The armature core |40 and the three iield cores |42, |43, |44 are separated from the pole pieces |28, |29 and the ring sections |25, |26 respectively, by an air lgap of about one eighth of an inch.

The armature Winding |48 is positioned in the eighteen slots |49 of the armature core |40 and is essentially one half of a bisected three-phase four pole Y-connected, two layer, lap winding. The three fieldcoils |50, |I, |52 are `wound on the cores |42, |43, |44 respectively and are excited by a 60 cycle alternating current. circuit for the field flux may be traced from a. iield coil, as |,5|, through the field core |43, extensions |45, armature core |40, pole piece |28 or |29, connection |30 or.|3|, laminated ring |25,` |26 and back to the field winding |5|. Similar and parallel paths are provided in connection with the eld coils |50 and |52.

The field flux in following the path just traced must thread some of the turns of the armature winding and, since the iiux is pulsating at the exciting'current frequency, a voltage of this frequency will be induced in the turns. of the armature winding. Consequently with each pole piece |28, |29 spanning approximately 90 electrical degrees of the armature winding, the magnitude of the induced 60 cycle Voltage in any given phase will vary from zero to'maximum to zero, will.

O Since the armature winding has three phases The` there are at all times three separate 60 cycle voltages induced in it displaced from each other by 120 and each following the cycle above described.

This transmitter is rugged in structure and easily installed without any machining of the shaft. The output of the transmitters provides current in form to drive the self synchronous units and the system provides for the development and indication of the propeller. data at any desired point on the ship. Readings are therefore provided giving not only the instant condition of the propellers as relative speeds and directions 'of rotation, but also the average speed and the totals of the revolutions and the mileage covered by the ship.

The system is simple and inexpensive and easily adaptable to a Wide variety of conditions.

The various data once determined may be repeated in any part of the ship so that each part has its own most desired information.

I claim:

1. In an indicating system for shafts of ships and the like, the combination with a driver adapted to rotate at a speed corresponding to the speed of one of said shafts, differential mechanism actuated on one input side from said driver, a constant speed motor having adjustable connecting mechanism driving the other input side of said diiferential, speed indicating means connected to the output side of said differential, and control means between said speed indicating means and the connection between the constant speed motor and thevdiiferential acting to control the rate of actuation of said differential by said motor.

2. In an indicating system for shafts of ships and the like, the combination with a plurality of electric motors adapted to continuously rotate at speeds corresponding to the relative speeds of said shafts, of differential means for combining the rotation of said motors to give the average total revolutions of said shafts; rate measuring means including means for combining the rotations of said drivers and acting to give the average speed of rotation of said shafts, indi-v cating means to show the total travel of the ship, and mechanism for driving said indicating means comprising connecting means from said differential means, control means driven from said rate measuring means and acting to vary said drive for said indicating means, and adjusting means independently movable to control said driving mechanism and provide an additional regulation of the indicating means.

3. An indicating system as set forth in claim 2 in which the rate measuring means combining the rotations vof the electric motors includes a constant speed motor differentially connected to each of said first mentioned motors. ARTHUR PA'I'I'ISON DAVIS. 

